1. Field of the Invention
The present invention relates to a method of testing a semiconductor device used, e.g., for high current switching.
2. Background Art
Japanese Laid-Open Patent Publication No. 2001-313367 discloses a semiconductor device in which a plurality of field limiting rings (FLRs) are formed in a termination structure. The FLRs serve to enhance the breakdown voltage, or dielectric strength, of the semiconductor device. A field insulating film formed by local oxidation of silicon (LOCOS) covers the portion of the principal surface of the substrate where the FLRs are formed.
It has been found, however, that if the insulating film of the termination structure is charged by polarization, the semiconductor device will exhibit an increased leakage current and an unstable dielectric strength in the dielectric strength test. The same problem arises if the semi-insulating film (if any) of the termination structure is charged. Therefore, it is necessary to remove charge from the insulating film and/or semi-insulating film of the termination structure.